ALASKAN GLACIER STUDIES
modified map of the ice tongues at the head of Blackstone Bay, and soundings throughout Blackstone and Portage Bays.
Topography. Blackstone Bay, a southwestern branch of Passage Canal just west of Port Wells, is about 11$ miles long and from one to two miles wide. It is a steep-walled fiord, but the walls are lower than those of Harriman Fiord and inner Passage Canal which penetrate the very heart of the mountains. Near the head of Blackstone Bay is the long, narrow Willard Island and a projecting peninsula; and around the head of the bay are eight small glaciers. On the southern side of the bay, close to Passage Canal, is a cove about a mile long, a short distance south of which is Tebenkof Glacier, the largest ice tongue of Blackstone Bay.
FIG. £1. SKETCH OF PASSAGE CANAL.
Tebenkof Glacier—Snoufields and Ice Tongue. Tebenkof Glacier (Fig. 52) is known to be over ten miles long and is from less than one to over two miles wide in the lower portion. It terminates over a half mile from the head of the cove, into which a number of large streams flow. Tebenkof Glacier also has two subordinate termini, which are lobes projecting from the side of the glacier into tributary valleys. The largest of these is about 4 miles from the terminus and projects westward for about a mile and a half, sending a glacial stream down to Blackstone Bay. The smaller lobe, which is on the eastern side about two miles south of the terminus, projects a shorter distance from the side of the glacier and its stream discharges eastward to Cochrane Bay.
The glacier heads on a high snow divide which is unexplored and it seems probable that the snowfields there coalesce with those that feed the smaller ice tongues to the west at the head of Blackstone Bay and the glaciers on the northwestern side of Port Nellie Juan. At least 10 miles south of the terminus of Tebenkof Glacier, there is another small glacier flowing northeastward from this same snowfield. It is about 2 miles long and its outlet stream flows eastward to Cochrane Bay about 2 miles distant. The absence of glaciers in Cochrane Bay on the east, and in Blackstone Bay on the